xref: /freebsd/share/man/man4/ng_hole.4 (revision ba54cdcdda639bebc917b1796ecbc35a83ff8625)
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33.\" Author: Archie Cobbs <archie@FreeBSD.org>
34.\"
35.\" $FreeBSD$
36.\" $Whistle: ng_hole.8,v 1.4 1999/01/25 23:46:26 archie Exp $
37.\"
38.Dd May 19, 2004
39.Dt NG_HOLE 4
40.Os
41.Sh NAME
42.Nm ng_hole
43.Nd netgraph discard node type
44.Sh SYNOPSIS
45.In netgraph/ng_hole.h
46.Sh DESCRIPTION
47The
48.Nm hole
49node type silently discards all data and control messages it receives.
50This type is used for testing and debugging.
51.Sh HOOKS
52A
53.Nm
54node accepts any request to connect, regardless of the hook name,
55as long as the name is unique.
56.Sh CONTROL MESSAGES
57This node type supports the generic control messages, plus the
58following:
59.Bl -tag -width indent
60.It Dv NGM_BPF_GET_STATS
61This command takes an
62.Tn ASCII
63string argument, the hook name, and returns the statistics
64associated with the hook as a
65.Vt "struct ng_hole_hookstat" .
66.It Dv NGM_BPF_CLR_STATS
67This command takes an
68.Tn ASCII
69string argument, the hook name, and clears the statistics
70associated with the hook.
71.It Dv NGM_BPF_GETCLR_STATS
72This command is identical to
73.Dv NGM_BPF_GET_STATS ,
74except that the statistics are also atomically cleared.
75.El
76.Sh SHUTDOWN
77This node shuts down upon receipt of a
78.Dv NGM_SHUTDOWN
79control message, or when all hooks have been disconnected.
80.Sh SEE ALSO
81.Xr netgraph 4 ,
82.Xr ng_echo 4 ,
83.Xr ngctl 8
84.Sh HISTORY
85The
86.Nm
87node type was implemented in
88.Fx 4.0 .
89.Sh AUTHORS
90.An Julian Elischer Aq julian@FreeBSD.org
91